PI3-kinase activation is critical for host barrier permissiveness to Listeria monocytogenes

Grégoire Gessain, Yu Huan Tsai, Laetitia Travier, Matteo Bonazzi, Solène Grayo, Pascale Cossart, Caroline Charlier, Olivier Disson, Marc Lecuit*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Invasion of nonphagocytic cells, a critical property of Listeria monocytogenes (Lm) that enables it to cross host barriers, is mediated by the interaction of two bacterial surface proteins, InlA and InlB, with their respective receptors E-cadherin and c-Met. Although InlA-E-cadherin interaction is necessary and sufficient for Lm crossing of the intestinal barrier, both InlA and InlB are required for Lm crossing of the placental barrier. The mechanisms underlying these differences are unknown. Phosphoinositide 3-kinase (PI3-K) is involved in both InlA- and InlB-dependent pathways. Indeed, InlA-dependent entry requires PI3-K activity but does not activate it, whereas InlB-c-Met interaction activates PI3-K. We show that Lm intestinal target cells exhibit a constitutive PI3-K activity, rendering InlB dispensable for InlA-dependent Lm intestinal barrier crossing. In contrast, the placental barrier does not exhibit constitutive PI3-K activity, making InlB necessary for InlA-dependent Lm placental invasion. Here, we provide the molecular explanation for the respective contributions of InlA and InlB to Lm host barrier invasion, and reveal the critical role of InlB in rendering cells permissive to InlA-mediated invasion. This study shows that PI3-K activity is critical to host barrier permissiveness to microbes, and that pathogens exploit both similarities and differences of host barriers to disseminate.

Original languageEnglish
Pages (from-to)165-183
Number of pages19
JournalJournal of Experimental Medicine
Issue number2
StatePublished - 9 Feb 2015


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